Permanent press fabric resin and process therefor

ABSTRACT

Crotonylidenediurea is reacted between about 2.80 molar proportions and about 5.0 molar proportions of formaldehyde in aqueous medium to produce an aminoplast material. When applied to a fabric and cured, the aminoplast material forms a finish which imparts permanent press properties to the fabric.

United States Patent 11 1 Tracy et al.

[ Apr. 8, 1975 PERMANENT PRESS FABRIC RESIN AND PROCESS THEREFOR [75]Inventors: James E. Tracy, Bernardsville; Alan L. Peterkoisky, Newark;William Lindlaw, Westfield, all of NJ.

[73] Assignee: Celanese Corporation, New York,

[22] Filed: Apr. 25, 1973 [21] Appl. No.: 353,835

Related U.S. Application Data [62] Division of Ser. No. 53.028, July 7,1970. abandoned.

[52] U.S. Cl. 1l7/139.4; 8/115.6; 8/115.7; 8/185; 8/186; 8/189; 117/143;117/138.8 A; l17/138.8 F; 260/676 C [51] Int. Cl. D06m 13/38; D06m 15/58[58] Field of Search 260/676 C, 67.7, 67.5; 117/1394; 8/185, 186

[56] References Cited UNITED STATES PATENTS 2.264.400 12/1941 Ott et a1260/69 X 2.600780 6/1952 Kohler 8/185 X 3.329.519 7/1967 Mills 106/1653.350.162 10/1967 Beck 8/185 X 3,386.940 6/1968 Tuites 8/185 X 3,539,28611/1970 Bowers et al. 8/185 X 3.634.019 1/1972 Beaumont et a1 8/185 X3.651.139 3/1972 Feinauer et a1 8/185 X 3,660,010 5/1972 Georgoudis eta1 8/185 X 3.771.950 11/1973 Schwartz et al. 8/185 X Primary Examiner-P.E. Willis, Jr. Attorney, Agem, 0r Firm-John A. Shedden; Kenneth A.Genoni; Thomas .1. Morgan [57] ABSTRACT Crotonylidenediurea is reactedbetween about 2.80 molar proportions and about 5.0 molar proportions offormaldehyde in aqueous medium to produce an aminoplast material. Whenapplied to a fabric and cured. the aminoplast material forms a finishwhich imparts permanent press properties to the fabric.

2 Claims, N0 Drawings PERMANENT PRESS FABRIC RESIN AND PROCESS THEREFORThis is a division of Ser. No. 53,028, filed July 7. 1970, nowabandoned.

BACKGROUND OF THE INVENTION This invention relates to a novel aminoplastmaterial. The invention also relates to a process for producing theaminoplast material and to the method for using same to impart permanentpress properties to fabrics, particularly cellulosic fabrics.

The term permanent press resins" is understood to mean substances which,when applied to fabrics, impart to the fabrics properties of wrinkleresistance and durable press". The property of wrinkle resistance (whichis synonomous with terms such as wrinkle-recovery, crease resistance,"and the like) refers to the ability ofa fabric to resist wrinkling andto retain smoothness of shape and hand upon repeated wear andlaundering. The property of durable press (which is synonomous withterms such as crease retention and the like) is understood to mean theability of a treated fabric to drip-dry without loss of crease and to beworn without ironing, although fastidious wearers may insist on sometouch-up" ironing.

Various methods are known for imparting permanent-press properties tofabrics, particularly fabrics derived from cellulosic materials (e.g.,regenerated cellulosic materials such as rayon and natural" cellulosicmaterials such as cotton and cotton-polyester blends and the like).However, these prior art techniques suffer a number of disadvantages.Thus, for example, some processes heretofore employed to impartpermanent-press properties to cellulosic fabrics result in finishedproducts which retain an undesirable amount of chlorine. thereby causingdamage to the fabrics. Moreover, it is generally recognized in thefabric finishing art that fabrics treated with heretofore knownpermanent press resins tend to be discolored and will experience furthersubstantial and unsightly discoloration on scorching. Accordingly, theoverall performance of heretofore known textile finishing agents leavesmuch to be desired. Thus, for permanent press white cottons, textilefinishing agents should impart to the substrate fabric a finish whichdoes not suffer nor otherwise cause acid damage to the substrate fabricas a result of hypochlorite bleaching, and should be durable to alkalineconditions normally encountered in laundering.

Therefore. it is an object of the present invention to provide a novelcomposition ofmatter which, when applied to a fabric, particularly acellulosic fabric, imparts a colorless, permanent press finish thereto,said finish having improved resistance to acid and alkaline degradationnormally encountered under ordinary bleaching and laundering conditions,which does not retain an undesirable amount of chlorine, and which doesnot cause substantial and unsightly discoloration of the fabric uponscorching.

Another object is to provide a process for producing a novel compositionof matter which, when applied to a fabric, and particularly to acellulosic fabric, imparts a colorless, permanent press finish thereto,said finish having improved resistance to acid and alkaline degra dationnormally encountered under ordinary bleaching and laundering conditions,which does not retain an undesirable amount of chlorine, and which doesnot cause substantial and unsightly discoloration of the fabric uponscorching.

Another object is to provide a permanent press fabric finish havingimproved resistance to acid and alkaline degradation normallyencountered under ordinary bleaching and laundering conditions, whichdoes not retain an undesirable amount of chlorine, and which does notcause substantial and. unsightly discoloration of the fabric uponscorching.

Yet another object is to provide a process for applying to a fabric, andparticularly to a cellulosic fabric, a permanent press finish, saidfinish having improved resistance to acid and alkaline degradationnormally encountered under ordinary bleaching and laundering conditions,which does not retain and undesirable amount of chlorine, and which doesnot cause substantial and unsightly discoloration of the fabric uponscorching.

These and other objects of the present invention, as well as a fullerunderstanding of the advantages thereof can be had by reference to thefollowing detailed description and claims.

SUMMARY OF THE INVENTION The above objects are achieved according to thepresent invention by the discovery of a novel composition of matterwhich, when applied to a fabric, particularly a cellulosic textilefabric, forms a coating or fabric finish which imparts excellentpermanent press properties to the treated fabric. More particularly,this novel composition of matter is produced according to the presentinvention by contacting crotonylidenediurea which has the followingformula:

H-N N-II l l jl with a specific amount of formaldehyde under carefullycontrolled reaction conditions. The product resulting from the reactionof crotonylidenediurea with formaldehyde according to the presentinvention is an aminoplast material comprising trimethylolcrotonylidenediarea which has the following structural formula:

HOH2CN N-CH2OH O Hue omort A H H The material crotonylidenediurea can bemade by reacting urea with acetaldehyde in an acidic hydroxylic medium,for example, as described in US. letters Pat. No. 3,190,741.

It is a feature of the present invention that the crotonylidenediureastarting material must be employed in a high state of purity, i.e., incrystalline form. In addition, it is especially important that thecrotonylidenediurea be free of color bodies or substances which giverise to color bodies which become noticeable when the aminoplast isapplied to a fabric, or during the lifetime of the treated fabric. Inthis connection, it has been discovered that the novel aminoplastmaterial of the present invention is not produced when formaldehyde iscontacted in situ with the crude reaction product of urea andcrotonaldehyde as described in US. letters Pat. No. 3,329,519. Sincecrotonylidenediurea has been postulated in the literature, e.g., 37Kunststoffe 165 (1947), as a product of the reaction between said ureaand crotonaldehyde. the formation of the herein novel aminoplastmaterial according to the present invention is a suprising andunexpected result.

Crotonylidenediurea suitable for use in the present invention isconveniently and preferably prepared according. to the followingprocedure, it being understood, of course, that other methods ofsynthesis can be used without departing from the spirit of theinvention: Thus, 270 parts by weight of urea are added to a mixtureof 99parts of acetaldehyde and 600 parts of distilled water in asuitable-conventional reaction vessel. The resultant solution is heatedto a temperature of about 60C. Thirty parts of phosphoric acid(catalyst) are then added and the temperature is thereafter maintainedat between about 60C. and about 70C for 1 hour. The reaction mixture issubsequently cooled to ambient temperature whereupon thecrotonylidenediurea crystallizes. This product is separated from thesupernatant liquid by filtration, washed with water, and dried in vacuo.The yield of white, solid, crotonylidenediurea (135.3 grams) is 66.9percent of the theoretical based on the weight of urea. Elementalanalysis of the product corresponds to the formula C,;H ,O N and theinfrared spectrum thereof (nujol mull) is identical to that reported inthe literature (cf. Japanese letters Pat. No. 492,348).

The reaction of crotonylidenediurea with formaldehyde to produce thenovel aminoplastic material of the present invention is accomplished bycontacting crotonylidenediurea with between about 2.80 and about 5.0molar equivalents of formaldehyde in a hydroxylic medium. The hydroxylicsolvent used should be capable of dissolving the reactants and alsocapable of being separated from the aminoplast material formed in thereaction by evaporative means. The preferred solvent is water. Theconcentrations of the reactants in the hydroxylic medium are notcritical provided the dissolution of the reactants can take place.However. in applying the novel aminoplast material of the presentinvention to a fabric, it is advantageous to do so by simply immersingthe substrate fabric into an aqueous solution of the aminoplastmaterial, said solution being simply the aqueous reaction mixture inwhich the aminoplast material is formed, modified, of course, by theaddition thereto of suitable curing catalyst of the type describedhereinbelow. Accordingly, the concentrationsof reactants are preferablythose which result in a concentration of aminoplast material which inturn determines the amount of resin pickup" experienced by the fabricwithin the pad bath.

In an especially preferred mode of the present process the reaction isconducted in formalin, i.e., an aqueous solution of formaldehyde inwhich the concentration of the latter is between about 35 and about 40percent. The amount of formaldehyde used can range between 2.80 and 5.0molar proportions, and preferably between about 2.90 and about 3.05molar proportions per molar proportion of crotonylidenediurea. The useof formaldehyde in amounts such that the molar ratio of formaldehyde tocrotonylidenediurea is less than about 2.80:1 is undesirable because thetrimethylol crotonylidenediurea would in such case be contaminated withsubstantial quantities of materials which tend to inhibit theperformance of the aminoplast material as a permanent press resin. Onthe other hand, the use of formaldehyde: crotonylidenediurea molarratios in excess of about 3.05:1 is less desirable, and the use ofratios in excess of about 5:1 is paticularly undesirable. The reason forthis is believed to be that when a quantity of formaldehyde is presentwhich substantially exceeds that which is stoichiometrically requiredfor the formation of the trimethylol crotonylidenediurea, such excesstends to contaminate the aminoplast material with formaldehyde and withby-products therefrom during the course of evaporative distillation toremove the excess formaldehyde or during curing operations, these beingprocesses which generally require elevated temperatures.

The reaction between crotonylidenediurea and formaldehyde according tothe present invention is catalysed by acid or base. In aqueous media,the reaction can be conducted at a pH of less than or greater than 7.Desirably, the reaction is conducted under basic conditions. Preferably,the reaction is conducted at a pH of greater than about 8 and less thanabout 12, with a pH of between about 9 and about 10 being especiallypreferred.

The temperature and pressure at which the crotonylidenediurea andformaldehyde are reacted are not critical. Desirably, the reaction isconducted at an elevated temperature and atmospheric pressure, with atemperature corresponding to the atmospheric reflux temperature of thereaction menstruum being preferred. The time required for completion ofthe reaction is generally less than 1 hour. The exact time requireddepends upon the reaction temperature, concentration of the catalyst(i.e., the pH) and reactants. A conventional titration method fordeterming when a particular reaction system has reached equilibrium isreferred to in connection with Example 1 hereinbelow.

The aminoplast material of the present invention is water-soluble, andis conveniently applied to a fabric as an aqueous solution. Accordingly,the reaction mixture, and preferably the aqueous reaction mixture, inwhich the aminoplast material is formed, can be used directly as the padbath solution into which the fabric to be treated is immersed or diptreated. The fabric is then wrung out by conventional means (e.g., be-

tween a pair of rollers) to remove excess liquid, and.

subsequently cured.

The curing of the aminoplast resin on the substrate. fabric is performedaccording to the present invention under conditions of elevatedtemperature and acid catalysis. A temperature of between about 50C andabout 200C is generally effective in curing the instant aminoplastmaterial to form a permanent press finish on the treated fabric.Preferably, a curing temperature of between about C and about 200C isemployed. The time required for curing depends upon the curingtemperature and catalyst concentration. Desirably, the curing step iscompleted between 1 and about 30 minutes and preferably between about 3and about 15 minutes. Substances suitable for catalysing the curingprocess include any conventional acidic catalyst or catalysts heretoforeknown to be useful in catalysing the curing of conventional aminoplastmaterials. Such acid catalysts are employed in conventional amountse.g., at a concentration of between about 1 percent and about 50 percentby weight based on the weight of aminoplast materials and includes as ageneral category those water-soluble inorganic salts which behave asso-called Bronsted acids. e.g., ammonium chloride, magnesium chloride,zinc nitrate, and the like.

According to a preferred mode of carrying out the fabric treatmentprocess of the present invention, the aqueous reaction mixturecontaining the novel aminoplast material dissolved therein is cooled toambient temperature, brought to a pH of about 7.0, and filtered toremove any insolubles which may or may not be present. Then, aconventional amount of an acidic curing catalyst is dissolved in thefiltrate, and the fabric to be treated is immersed therein. The amountof resin picked-up" by the substrate fabric is determined in largemeasure by the concentration of the aminoplast material in the aqueouspad-bath solution. Generally, the concentration of theaminoplast-material in the pad bath solution (which can be determinedgravimetrically) ranges between about 2 percent or less and about 65percent by weight or more for cellulosic fabrics. Preferably. a pad-bathconcentration of between about 5 percent and about 45 percent is used,with a concen tration of between percent and about percent beingespecially preferred. The particular desired concentration of aminoplastmaterial in any given instance is conveniently achieved by appropriateadjustment of the concentrations of reactants (i.e., fofmaldehyde andcrotonylidenediurea) or by the judicious addition of water to aninitially relatively highly concentrated solution of aminoplastmaterial.

After saturating the fabric with the pad-bath solution, the treatedfabric is withdrawn from the bath, wrung between rollers made of aninert material (e.g., metal, ceramic, and the like), preferablystainless steel rollers, and simultaneously or subsequently heat curedat a temperature within the aforementioned range. The heat curing stepcan. if desired, be conducted by contacting the fabric with heated metalrollers, preferably heated stainless steel rollers, which rollers canbe-the same or different than the rollers used in the wringingoperation.

Fabrics, particularly cellulosic fabrics, treated with the aminoplastmaterial according to the present invention exhibit excellent permanentpress properties. In addition, such fabrics are free of undesirableamounts of chlorine, and white fabrics so treated are not discolored nordoes appreciable discoloration occur upon aging or scorching.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples arepresented for the purpose of illustrating (but not limiting) the presentinvention. In the examples, parts and percentages are by weight unlessotherwise indicated.

EXAMPLE 1 This example illustrates the novel aminoplast of the presentinvention and the process for producing same.

To a suitable reaction vessel equipped with conventional agitation meansare charged 239 grams (2.94 moles) of 37 percent formalin (uninhibited")and 15 grams of a 10 percent aqueous solution of sodiumcarcrotonylidenediurea. The reaction mixture, which has a pH of betweenabout 9 and about 9.5, is heated to reflux temperature over the courseof about 20 minutes and maintained at the reflux temperature for about 5minutes. The reaction mixture is then cooled to ambient temperature, thepH is adjusted to 7.0, and the reaction mixture filtered to removeinsolubles. The clear filtrate contains 2.8 percent free formaldehyde asdetermined by the sodium sulfate method" described in Walker,Formaldehyde, 3d ed.., p 486 (Reinhold, NY. 1964). The concentration ofaminoplast material in the aqueous filtrate is 60 percent by weight asdetermined gravimetrically, i.e., by evaporating an aliquot sample ofthe solution at C. for 6 hours and weighing the residue.

EXAMPLE 2 This example illustrates a variant of the procedure used inExample 1 to produce the trimethylol crotonylidenediurea aminoplastmaterial of the present invention.

To a suitable reaction vessel equipped with conventional agitation meansare chared 4,055 grams (50 moles) of 37 percent formalin (uninhibited")and grams of a 10 percent aqueous solution of sodium carbonate. To theresulting mixture are added, with agitation, 1720 grams (10 moles) ofcrystalline crotonylidenediurea. The reaction mixture is then heated atreflux temperature for 5 minutes and cooled to ambient temperature. Anadditional charge of 150 grams of 10 percent aqueous sodium carbonateand 1204 grams (7 moles) of crotonylidenediurea are added and thereaction mixture is again heated to reflux temperature and maintainedthereat for 30 min utes. Upon recooling the reaction mixture to ambienttemperature, neutralizing the pH, and filtering, a solution oftrimethylol crotonylidenediurea is obtained which contains 2.7 percentunreacted formaldehyde.

EXAMPLE 3 This example illustrates the process of treating a cellulosicfabric (100 percent cotton) with the trimethylol crotonylidenediureaaminoplast material of the present invention.

The pad baths used in this evaluation were prepared at two differentconcentrations, namely, 10 percent by weight permanent press resin and25 percent by weight permanent press resin. Twenty percent Zinc nitrate(curing catalyst) based on the weight of aminoplast material was alsoincluded in each pad bath.

Four samples of light-weight cotton fabric were treated with each padbath solution for a total of 8 samples. Four addition samples served ascontrols." The odd-numbered samples were cured for three minutes at C.and the even numbered samples were cured for 6 minutes at 165C. Of thetwo odd numbered samples that were treated with each solution, onesample was laundred (in Tide) one time and the other sample waslaundered 25 times. The fabric samples were rated for hand, appearance,tear strength and wash-wear appearance. The results are summarized inTable l.

Table I Permanent Press Treatment of I Percent Lightweight Cotton FabricWash-Wear Tear Strength Appearance Hand (2) Appearance After SampleNumber of After After After After After Laundering (3) No. TreatmentLuandcrings Curt Laundering Cure Laundering Laundering (2) Warp I NoTreatment I OK no change I l l 4.4 4.2 2 do. 1 do. do. I l l 3.0 2.2 3do. 25 do. do. I l l 2.6 3.6 4 do. 25 do. do. I I 2 3.5 3.0

5 '71 Pad-Bath 1 OK. do. I l 4 3.7 3.5 6 do. I V.Sl.Ycllo\\ do. 1 1 4-53.5 3.3 7 do. O.K. do. I I 4-5 3.7 2.6 8 do. 25 V.SI.Yellow do. I I 53.6

9 2571 Pad-Bath l O.K. do. 1-2 l 5 2.9 10 do. I SLYeIlow do. I-2 I 5 3.3I I do. 25 O.K. do. l-2 I 5 2.6 I2 do. 25 SLYellow do. 1-2 I 5 2.6

(I A rating of l is \ery wrinkled and a rating of 5 is wrinkle-free(excellent durable press). The test procedure used is described in AAATCNo. l24-I967 (2) A rating of l corresponds to an acceptably "soft feel:a rating of 5 corresponds to an undesirably stiff feel.

(3) Measurements of tear strength (in pounds) are made on an ElmendorfTear Tester.

EXAMPLE 4 The aqueous pad bath used in this example has the We claim: 1.A process for imparting a permanent press finish to a fabric comprising:

a. contacting the fabric with an aqueous solution of an aminoplastmaterial comprising a compound having the following structural formula:

ollowrng composition: -HOH2C-N N-CHzOH CHQOH o t... Aminoplast 20percent H H 5 b. conducting step (a) 1n the presence of an acid curzincnitrate (curing catalyst) 4 percent (i.e.. 20 mg catalyst; and

Psrcem a the c. subsequently exposing the fabric treated in step percentof ammoplast I 0 present) (b) to a temperature of at least about 50 C.to cure the aminoplast material. Emersoft 7777 (softener) 3 percent 2. Aprocess according to claim 1 wherein:

the fabric is a cellulosic fabric; Trim" X4000 05 percent theconcentration of the aminoplast material in the aqueous solution used 1nstep (a) IS between about d d 2 percent and about 65 percent by weight;Three 5amples (Nos; 7 9) 0ff1bnc are treats decor the acid curingcatalyst used in step (b) is selected mg to the present mvemlon l three.sampkis T from the group consisting of inorganic salts which 1-3) areused as a control. After immersion, t e behave as Bronsted acids; andsamples are wrung and cured for five minutes at 170 C. the temperatureemployed in Step (c) is between Test results for the treated fabric aresummarized 1n about 100C and about 200C. Table TABLE II Permanent PressTreatment of 50/50 Polyester/Cotton Poplin Blend Tear Strength HandAppearance After Laundering Sample Number of After After After AfterAfter Warp Fill No. Treatment Launderings Cure 1 Wash 25 Washes CureLaundering 1 No Treatment 25 2 l l O.K. O.K. 7.5 6.5 2 do. I 2 l do. do.8.6 6.6 3 do. I 2 I do.

7 20'71 Pad-Bath 25 3-4 2-3 2 do. O.K. 5.6 5.4 8 do. 1 3-2- do do. 6.85.3

2-3 9 do. 1 3-4 2-3 do.

1. A PROCESS FOR IMPARTING A PERMANENT PRESS FINISH TO A FABRICCOMPRISING: A. CONTACTING THE FABRIC WITH AN AQUEOUS SOLUTION OF ANAMINOPLAST MATERIAL COMPRISING A COMPOUND HAVING THE FOLLOWINGSTRUCTURAL FORMULA:1,3-DI(HO-CH2-),2-(O=),4-(HO-CH2-NH-CO-NH-),6-(CH3-)PYRIMIDINE B.CONDUCTING STEP (A) IN THE PRESENCE OF AN ACID CURING CATALYST, AND C.SUBSEQUENTLY EXPOSING THE FAFABRIC TREATED IN STEP (B) TO A TEMPERATUREOF AT LEAST ABOUT 50*C. TO CURE THE AMINOPLAST MATERIAL.
 2. A processaccording to claim 1 wherein: the fabric is a cellulosic fabric; theconcentration of the aminoplast material in the aqueous solution used instep (a) is between about 2 percent and about 65 percent by weight; theacid curing catalyst used in step (b) is selected from the groupconsisting of inorganic salts which behave as Bronsted acids; and thetemperature employed in step (c) is between about 100.degree.C. andabout 200.degree.C.